1. Field of the Invention
This invention relates to devices for measuring temperature, more specifically to infrared thermometers primarily intended for medical applications.
2. Description of the Related Art
An infrared (IR) medical ear thermometer is well known in the art. A typical ear thermometer comprises an infrared sensor being coupled to a probe that is adapted for partial insertion into an ear canal and is aimed in the direction of the tympanic membrane. This device essentially is a non-contact optoelectronic device that measures intensity of infrared radiation that emanates from the ear canal surface area and the device converts the IR signal into an output temperature reading. These thermometers are exemplified by U.S. Pat. Nos. 4,797,840 and 4,854,730 issued to Fraden. When designed correctly, IR ear thermometers can be very accurate instruments and enjoy a deserved acceptance in the medical services. Most of the IR ear thermometers operate with disposable or reusable probe covers that envelope a portion of the probe that may come in contact with the patient's skin. These probe covers incorporate a polymer membrane which is substantially transparent to IR radiation. The probe covers are exemplified by U.S. Pat. No. 5,795,067 issued to Fraden et al.
Even though an ear IR thermometer is a non-contact instrument and generally considered non-invasive, in practice it still requires insertion into the patient's ear canal and thus can be somewhat disturbing, especially for pediatric patients. One skilled in the art of medical thermometry would also know of an alternative, albeit less accurate IR thermometer that measures the IR (thermal) radiation from the patient's external body surface such as a forehead in the temporal region. A probe of the surface thermometer is in direct contact with the skin and also may be moved along the skin in order to locate the warmest skin region. These thermometers are exemplified by U.S. Pat. No. 6,292,685 issued to Pompei. A disposable probe cover also can be used together with this type of a thermometer. The probe cover is exemplified by U.S. Pat. No. 6,932,775 issued to Pompei. Some efforts have been made to modify the IR thermometer by employing special probes for different body sites, such as the ear, axilla, or forehead. This is exemplified by the teachings of U.S. Patent Publication No. 2007/0189358 issued to Lane et al. Another application of an IR medical thermometer is for measurements of temperatures from a distance ranging from a few centimeters to a few meters with no contact with the patient whatsoever. These devices closely relate to thermal imaging systems and are exemplified by U.S. Pat. No. 4,498,881 issued to Everest, U.S. Pat. No. 7,340,293 issued to McQuilkin, and U.S. Patent Application Publication No. 2007/0153871 to Fraden. The entire disclosure of the above mentioned patents and patent applications are incorporated by reference herein.
All the above referenced devices have at least one thing in common—an IR sensor. This sensor is an essential part of the most popular medical IR thermometer—an ear thermometer. It would be highly desirable instead of using separate thermometers or attachments for various body sites to use just one ear thermometer that can be adapted for use with multiple sites of the human body. Thus, there is a need for a thermometer that can be easily converted from an IR ear thermometer to an IR thermometer that can be used on other body sites, either by means of touching the patient or a contactless measurement.